if I were和if I am的区别

if I were和if I am的区别 If I were a bird 和If I am a bird 有什么区别? If I were a boy与If I am a boy.的的区别,为什么I 后面可以用were? If I am a boy 和 If I were a boy 有区别吗,可不可以互换?可以用在相同的地方吗 at school in school 的区别?还有if i was you 和 if i were you的区别? if i were you i will/would的区别 if I have 和If I had的区别 was不是is和am的过去式吗?were不是are的过去式吗?为什么可以用if i were a boy?而不用if i if i were you 跟if i did you的区别 If i were U. if i were you if i were a